Specifies one of three states for the default ring: normal,
active, or disabled. In active state, the button is drawn
with the platform specific appearance for a default button. In normal
state, the button is drawn with the platform specific appearance for a
non-default button, leaving enough space to draw the default button
appearance. The normal and active states will result in buttons of
the same size. In disabled state, the button is drawn with the
non-default button appearance without leaving space for the default
appearance. The disabled state may result in a smaller button than
the active state.

Specifies a desired height for the button.
If an image or bitmap is being displayed in the button then the value is in
screen units (i.e. any of the forms acceptable to Tk_GetPixels);
for text it is in lines of text.
If this option is not specified, the button's desired height is computed
from the size of the image or bitmap or text being displayed in it.

Specifies an alternative relief for the button, to be used when the
mouse cursor is over the widget. This option can be used to make
toolbar buttons, by configuring -relief flat -overrelief
raised. If the value of this option is the empty string, then no
alternative relief is used when the mouse cursor is over the button.
The empty string is the default value.

Specifies one of three states for the button: normal, active,
or disabled. In normal state the button is displayed using the
foreground and background options. The active state is
typically used when the pointer is over the button. In active state
the button is displayed using the activeForeground and
activeBackground options. Disabled state means that the button
should be insensitive: the default bindings will refuse to activate
the widget and will ignore mouse button presses.
In this state the disabledForeground and
background options determine how the button is displayed.

Specifies a desired width for the button.
If an image or bitmap is being displayed in the button then the value is in
screen units (i.e. any of the forms acceptable to Tk_GetPixels).
For a text button (no image or with -compound none) then the width
specifies how much space in characters to allocate for the text label.
If the width is negative then this specifies a minimum width.
If this option is not specified, the button's desired width is computed
from the size of the image or bitmap or text being displayed in it.

The button command creates a new window (given by the
pathName argument) and makes it into a button widget.
Additional
options, described above, may be specified on the command line
or in the option database
to configure aspects of the button such as its colors, font,
text, and initial relief. The button command returns its
pathName argument. At the time this command is invoked,
there must not exist a window named pathName, but
pathName's parent must exist.

A button is a widget that displays a textual string, bitmap or image.
If text is displayed, it must all be in a single font, but it
can occupy multiple lines on the screen (if it contains newlines
or if wrapping occurs because of the wrapLength option) and
one of the characters may optionally be underlined using the
underline option.
It can display itself in either of three different ways, according
to
the state option;
it can be made to appear raised, sunken, or flat;
and it can be made to flash. When a user invokes the
button (by pressing mouse button 1 with the cursor over the
button), then the Tcl command specified in the -command
option is invoked.

Query or modify the configuration options of the widget.
If no option is specified, returns a list describing all of
the available options for pathName (see Tk_ConfigureInfo for
information on the format of this list). If option is specified
with no value, then the command returns a list describing the
one named option (this list will be identical to the corresponding
sublist of the value returned if no option is specified). If
one or more option-value pairs are specified, then the command
modifies the given widget option(s) to have the given value(s); in
this case the command returns an empty string.
Option may have any of the values accepted by the button
command.

Flash the button. This is accomplished by redisplaying the button
several times, alternating between active and normal colors. At
the end of the flash the button is left in the same normal/active
state as when the command was invoked.
This command is ignored if the button's state is disabled.

Invoke the Tcl command associated with the button, if there is one.
The return value is the return value from the Tcl command, or an
empty string if there is no command associated with the button.
This command is ignored if the button's state is disabled.

A button activates whenever the mouse passes over it and deactivates
whenever the mouse leaves the button.
Under Windows, this binding is only active when mouse button 1 has
been pressed over the button.

[2]

A button's relief is changed to sunken whenever mouse button 1 is
pressed over the button, and the relief is restored to its original
value when button 1 is later released.

[3]

If mouse button 1 is pressed over a button and later released over
the button, the button is invoked. However, if the mouse is not
over the button when button 1 is released, then no invocation occurs.

[4]

When a button has the input focus, the space key causes the button
to be invoked.

If the button's state is disabled then none of the above
actions occur: the button is completely non-responsive.

The behavior of buttons can be changed by defining new bindings for
individual widgets or by redefining the class bindings.